Which order provides guidance for managing air traffic facilities?

The order that provides guidance for managing air traffic facilities is indeed 7210.3. This document outlines the procedural and operational protocols that air traffic facilities should follow, ensuring that air traffic control processes are standardized and effective across different locations. It serves as a comprehensive manual that addresses everything from facility management to air traffic control services, which is critical for maintaining safety and efficiency in the National Airspace System.

The other choices refer to different orders with specific focuses. For instance, 7350.9 deals with aviation-related land use planning and how it impacts safety and efficiency, while 7600.2 is focused on communications procedures related to general aviation. Lastly, 8900.1 provides guidance on the FAA's evaluation procedures for safety management systems but does not directly address facility management in the same manner as 7210.3. Understanding the specific focus of each order helps clarify why 7210.3 is the correct answer for guidance on managing air traffic facilities.